An LED module is known, which includes at least two areas including mounted LEDs as components on a mounting substrate on which a plurality of LEDs is mounted and is capable of implementing high color rendering properties and a color control function by emitting light whose emitted light colors are different from the at least two areas (see Patent Document 1 to Patent Document 7). For example, the LED module described in Patent Document 1 includes a plurality of belt-shaped light-emitting areas each of which emits light having one of a first emitted light color and a second emitted light color.
FIG. 15 is a plan view of an LED module, which is a light-emitting device including a plurality of belt-shaped light-emitting areas.
An LED module 801 includes a mounting substrate, not illustrated, a first light-emitting unit group 811 that emits light having a first color temperature, a second light-emitting unit group 812 that emits light having a second color temperature, a first power source 813, a second power source 814, and a controller 815. Each of the first light-emitting unit group 811 and the second light-emitting unit group 812 is arranged on the mounting substrate in a predetermined array pattern. The first power source 813 and the second power source 814 are isolated from each other. The first light-emitting unit group 811 is supplied with a current from the first power source 813 and the second light-emitting unit group 812 is supplied with a current from the second power source 814. The controller controls a ratio between the currents supplied to the first light-emitting unit group 811 and the second light-emitting unit group 812 from the first power source 813 and the second power source 814, respectively.
The first light-emitting unit group 811 has a plurality of LED chips 821 that emit blue light and a first phosphor layer 831 that seals the plurality of LED chips 821 and includes a first phosphor. The second light-emitting unit group 812 has a plurality of LED chips 822 that emit blue light, a second phosphor layer 832 that seals the LED chips 822, and a second phosphor layer 812 that is arranged on the second phosphor layer 832 and includes a second phosphor. The second light-emitting unit group 812 emits light having a color temperature lower than that of the light emitted by the first light-emitting unit group 811.
In the LED module 801, a belt-shaped pattern may be visually recognized on an irradiation surface. In order to prevent the belt-shaped pattern from being visually recognized on the irradiation surface, Patent Document 1, describes the embodiment in which a first light-emitting unit group that emits a first emitted light color and a light-emitting unit group that emits a second emitted light color are arrayed in the form of a checkered pattern to improve color mixing properties. However, if the light-emitting unit group that emits the second emitted light color is arrayed in the form of a checkered pattern, there is such a problem that the wiring system structure and the manufacturing process of the LED module become complicated.
It is known that the light-emitting area is circularly formed, in order to make easy optical design of a lens or the like, as well as to prevent an arrangement pattern of a light-emitting area from being visually recognized. For example, Patent Document 8 describes an LED module in which two areas are arranged concentrically.
FIG. 16 is a plan view of an LED module 901 in which two areas are arranged concentrically.
The LED module 901 includes a mounting substrate 900, a light-emitting unit 910 including a first LED 911 and a second LED 912, a dam material 920 including a first dam material 921 and a second dam material 922, and a fluorescent resin 930 including a first fluorescent resin 931 and a second fluorescent resin 932. The first dam material 921 and the second dam material 922 are concentric dam materials and the first dam material 921 is arranged inside the second dam material 922. A first light-emitting area N1 including the first LED 911 and the first fluorescent resin 931 is formed inside the first dam material 921. A second light-emitting area N2 including the second LED 912 and the second fluorescent resin 932 is formed between the first dam material 921 and the second dam material 922. The first light-emitting area N1 and the second light-emitting area N2 emit light having color temperatures different from each other. For example, the color temperature of the first light-emitting area N1 is 3,500 K and the color temperature of the second light-emitting area N2 is 6,500 K. The first light-emitting area N1 and the second light-emitting area N2 are circular, and therefore the LED module 901 may implement illumination light with high color mixing properties by comparatively easy optical design.